Performance: Eevee vs Blender Internal
I know I'm late to the party, but I'll leave this here for reference. Blender Internal is an extremely outdated engine, hence why they replaced it in 2.80 with Eevee, which is far superior in every way.
The most prominent difference between Eevee and Blender Internal is that, while Blender Internal renders offline using the CPU only when you manually go to render, Eevee is a real-time rendering engine that runs on the GPU utilizing OpenGL. This means that Eevee is significantly faster than Internal in every situation, even when rendering on the CPU. In fact, Blender 2.80's material view actually utilizes Eevee for its rendering.
Furthermore, Eevee is much easier to use and has a node-based material system identical to that of Cycles, including PBR support. (Eevee materials are actually compatible with Cycles and vice-versa.) No longer do you have to fiddle with a million settings in order to get a decent result, although optimization settings are still present and very powerful for those so inclined. But your optimization (or lack thereof) in the scene will only ever affect render times in matters of seconds, as the main bottleneck when it comes to Eevee is the time it takes Blender to save the frame to disk and queue up the next frame.
In short, use Eevee and your render times will be faster and your results will look way better.
PS: I don't actually know that much about the technical side of Blender Internal, so forgive me if I got something wrong.